<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<title></title>
		<style type="text/css">
			/*继承性*/
			#box{
				color: red;
			}
			
			/*叠加性*/
			#box span{
				font-size: 30px;
			}
			#box .two{
				background: yellow;
			}
			
			#box .three{
				color: blue;
			}
		</style>
	</head>
	<body>
		<div id="box">
			<!--span.in{我们都是span标签}*3-->
			<span class="one">我们都是span标签</span>
			<span class="two" style="color: blue;">我们都是span标签</span>
			<span class="three" style="color: yellow;">我们都是span标签</span>
		</div>
	</body>
</html>
